He has evolved from conservative insurgent to cunning Washington insider, then enjoyed lucrative contracts with Fox News and Washington lobbying and consulting firms.

Reporting from Washington — Rick Santorum first came to Congress from western Pennsylvania in 1990 after waging a grass-roots campaign against an opponent he labeled a Washington insider for buying a house in a fancy suburb of the capital.

But during four years in the House and 12 in the Senate, Santorum became an insider himself. He brought home earmarks that his competitors are now criticizing. He helped lead Republican outreach to K Street lobbyists. And despite his campaign promises, Santorum established his family's home in an affluent Washington suburb while charging his children's school tuition to Pennsylvania taxpayers.

The shift from conservative insurgent to a man considered a cunning Capitol player dogged Santorum in his 2006 Senate race, in which his Democratic challenger, Bob Casey, branded him beholden to Washington interests. Santorum lost his seat in a double-digit rout.

Since leaving the Senate, Santorum has quietly built a comfortable life, following a path that has become well-worn for former members of Congress. He doubled his net worth with lucrative contracts with Fox News and Washington lobbying and consulting firms.

Now his squeaker second-place finish behind GOP presidential front-runner Mitt Romney in the Iowa caucuses has brought renewed scrutiny to the former senator's record. Santorum's campaign did not respond to requests for comment for this story.

Santorum started his political career with an upset, unseating seven-term Democrat Doug Walgren by a 2-point margin. Santorum relentlessly criticized Walgren for living in "the wealthiest area of Virginia," hundreds of miles away from the eastern suburbs of Pittsburgh that he represented. Walgren said in an interview this week that the residency issue was "the key" to the election.

"He made a lot of absolute promises that he would never live in Washington, that his residence has always been in Pittsburgh," Walgren said.

But four years later, when he was elected to the Senate, Santorum and his family settled into a home in Herndon, Va., and then moved to a larger house, purchased for $643,000 in affluent Leesburg.

"He found out that [keeping his family in Pittsburgh] was not something that he wanted to do," Walgren said. "He accused me of doing something that he said was wrong and then just went right ahead and did it himself."

Santorum has told Pennsylvania reporters that his pledge not to live in Washington applied to his service in the House. "The Senate is a very different place," he said, according to the York (Pa.) Daily Record.

On Capitol Hill, Santorum at first took an anti-establishment tack, joining other GOP freshmen to expose the fact that more than 350 representatives, Democrats and Republicans alike, had written thousands of overdrafts on the now-defunct House bank.

As his tenure went on, Santorum went from needling the establishment to becoming the establishment, ascending the ranks to be the third-highest Republican in the Senate. From that position, he worked on legislative successes, including passage of a massive welfare reform bill during the Clinton presidency.

But he also came under fire. Santorum enrolled five of his children in an online Pennsylvania charter school in Penn Hills at an estimated cost to Pennsylvania taxpayers of $72,000. Under Pennsylvania law, school districts must pay the tuition of a student who chooses cyber-school, as well as charges for computers, Internet connection fees and evaluation services.

But the Santorum kids were not living in Pennsylvania, according to an ethics complaint filed by Citizens for Responsibility and Ethics in Washington. Virginia, their home state, only required local districts to pay for private education of students with disabilities who are enrolled in public schools that cannot meet their needs, according to the complaint. The Senate ethics committee never responded.

In a Sept. 2006 speech, Santorum pushed back against critics.

"I defend it as I'm a taxpayer in Penn Hills, Pa. That's where I pay my income tax, that's where I pay my real estate tax, that's where I pay wage taxes, state taxes, I pay taxes like any other state taxpayer," said Santorum, according to a Pittsburgh Post-Gazette report.

Another controversy arose over Santorum's relationship with K Street lobbyists, named after the avenue in Washington that is home to some of the nation's most powerful lobbying organizations. Every two weeks, Santorum conducted meetings in the Capitol with top lobbyists, discussing a wide range of topics, including job openings in lobbying shops.